The present invention relates to apparatus for assembling or building blocks of parallel rod-shaped articles, particularly rod-shaped articles which contain tobacco and are ready to be introduced into a packing machine or into another processing machine for smokers' products. Still more particularly, the invention relates to improvements in apparatus for assembling multi-layer blocks or arrays of plain or filter-tipped cigarettes, cigars or cigarillos.
It is known to connect the magazine at the inlet of a cigarette packing machine with two groups of downwardly extending ducts which convey cigarettes sideways to a block forming station. Each duct of one group communicates with a duct of the other group at the block forming station and those end portions of the ducts which are located at such station are horizontal and disposed one above the other. A pusher is caused to perform periodic working strokes in the axial direction of cigarettes which accumulate at the block forming station to expel a block of cigarettes into the pocket of an indexible turret or an analogous conveyor for blocks of cigarettes. Since the cigarettes descent in their ducts by gravity, the frequency at which a block can be expelled by the pusher depends on the length of intervals which are needed to allow for refilling of the end portions of ducts at the block building station with fresh cigarettes subsequent to retraction of the pusher. Attempts to accelerate the filling of ducts at the block forming station include the provision of a greatly increased number of pairs of communicating ducts, e.g., one pair for each cigarette of a layer of cigarettes in a block. Such mode of assembling blocks is satisfactory when a block comprises a substantial number of layers, e.g., three layers of seven cigarettes each or two layers of seven cigarettes each and an intermediate layer of six cigarettes. However, the operation of such apparatus is unsatisfactory when the number of layers is small (e.g., two) and each layer consists of a large number of cigarettes (e.g., ten). The walls of neighboring ducts then occupy so much space that the conversion of cigarettes which fill the block forming station into a block of ultimate size and shape necessitates substantial lateral movement of all or nearly all cigarettes during expulsion from the block forming station. The situation is aggravated by the fact that the width of each duct must exceed the diameter of a cigarette in order to avoid jamming and the resulting lengthy interruptions in operation of block forming apparatus.